Peripheral nerve blocks of lower limbs and paravertebral blocks. Regional Anesthesia

1. Peripheral Nerve Blocks of
Lower Extremity &
Paravertebral Blocks
By – Dr. Rohit Saini
Moderator – Dr. L.S.Misra &
Dr. Manish Singh

2. Techniques for localising Neural
structures
1. Paraesthesia technique – elicited when a
needle makes direct contact with a nerve.
2. Peripheral Nerve stimulation – transmits
small electric current through tip of needle
which causes muscle contraction.
3. Ultrasound guided – allows visualization of
nerve target & surrounding structures.

3. Lower Extremity blocks
The nerve supply to lower extremity is derived from
lumbar & sacral plexus.
1. Lumbar plexus – formed by anterior rami of L1–
L4 (occasionally including branches from T12 &
L5).
• Anterior division forms Obturator nerve (L2-L4).
• Posterior division forms –
i). Femoral nerve (L2-L4) which continues as
Saphenous nerve and
ii). lateral femoral cutaneous nerve (L2-L3).

4. Lumbar Plexus

5. Lower Extremity blocks
2. Sacral plexus – gives off two nerves from anterior
rami:
• Posterior cutaneous nerve of thigh (S1-S3).
• Sciatic nerve (L4-S3) – further separates at or
above popliteal fossa into:
i). Tibial nerve (anterior division) - further into
Posterior tibial nerve & Sural nerve.
ii). Common Peroneal nerve (posterior division) –
further into Deep & Superficial peroneal nerve.

6. Cutaneous distribution of lower
extremity

7. Psoas compartment block
Lumbar plexus lies between Psoas major muscle
& Quadratus lumborum.
Clinical application :
• Combined with sciatic nerve block for
anaesthesia of entire lower extremity.
• Post operative analgesia for major knee & hip
surgery.

8. Technique
Classic technique

9. Technique
Modified classic psoas technique
(by Capdevilla & colleague)

10. Perivascular three in one (Femoral)
block
A large volume of local anaesthetics injected
into femoral canal while maintaining distal
pressure leads to proximal spread underneath
the fascia iliaca into psoas compartment and
subsequent lumbar plexus blockade.
Clinical application :
• Anaesthesia for knee arthroscopy.
• Analgesia for femoral shaft fracture & knee
surgeries.

11. Femoral block
Technique:
• Classic approach
• Modified femoral
(Fascia iliaca nerve
block) – double pop
sensation (sensation of
fascia lata and then
fascia iliaca).

12. Lateral femoral cutaneous nerve
block
Technique – 2 cm lateral & 2 cm caudal to ASIS,
after getting pop sensation of fascia lata &
iliaca inject 10 – 15 ml of LA.
Clinical application :
• Useful for skin harvesting.
• In combination with other nerve blocks for
surgery of thigh.
• Fascia lata pain syndrome.

13. Obturator nerve block
Clinical application :
• For knee surgery (in combination with other
nerve blocks).
• Painful hip joint
• Painful knee joint.
• For adductor spasms (in cerebral palsy or
other neurologic diseases).
• Supplement with neuraxial blockade for
TURBT (mass on lateral wall of urinary
bladder).

14. Technique
1. Classic technique

15. Technique
1. Classic approach
2. Interadductor
approach (by
Wasseff).
3. Inguinal approach
(recently described).

16. Saphenous
nerve block
It innervates medial aspect
from knee to medial
malleolus.
Technique :
1. Paravenous approach.
2. Trans sartorial
approach.
3. Localised field block.
4. Block at medial
malleolus (part of
ankle block).

17. Parasacral block
It blocks both sciatic nerve and posterior
cutaneous nerve of thigh. It may also
anaesthetise superior and inferior gluteal
nerves, pudendal nerves, pelvic splanchnic
nerves, inferior hypogastric nerve.
Clinical application :
• For below knee surgeries.
• Also useful when access to individual nerves
of sacral plexus is not possible (like in trauma
or infection).

18. Parasacral block

19. Sciatic nerve block
Clinical application :
• Combined with saphenous nerve block, any
surgical procedure below knee where thigh
tourniquet is not required.
• Combined with other nerve blocks for thigh
and knee surgeries.

20. Classic (posterior) approach of Labet
{modified sim’s position}

21. Sciatic nerve
block
Classic
(posterior)
approach of
Labet

22. Subgluteal approach
{in modified sim’s position}

23. Anterior approach

24. Popliteal fossa block
Clinical application : Combined with saphenous
nerve block for foot and ankle surgeries where
calf tourniquet or Esmarch bandage is
required.
Techniques:
• Posterior approach
• Lateral approach

25. Posterior approach

26. Lateral approach

27. Nerve block at the ankle
Clinical application : for surgery of foot where
calf tourniquet is not required.
Techniques :
• Posterior tibial nerve block
• Sural nerve block
• Deep & Superficial peroneal nerve and
Saphenous nerve block.

28. Posterior tibial & Sural nerve block

29. Deep & Superficial peroneal nerve and
Saphenous nerve block.

30. Complications
1. Nerve injury – risk factors :
• Traumatic injury with needle or catheter.
• High dose or high concentration or prolonged
exposure to local anaesthetics.
• Infection
• Intraoperative improper positioning.
• Tightly applied casts or dressings.
• Surgical trauma.

31. Complications
2. Haemorraghic complications – range from simple
bruising to large tender hematomas.
3. Intravascular injection (LAST) – leads to CNS and
CVS toxicity.
4. Intrathecal or Epidural administration of LA (like
in psoas compartment block, paravertebral block,
parasacral block).
5. Infection – Exogenous (by contaminated drug or
equipment) or endogenous (bacteremia or
sepsis).

32. Thoracic paravertebral block (TPVB)
TPVB is the technique of injecting LA alongside the
thoracic vertebra close to where spinal nerves
emerge from intervertebral foramen. This produces
• unilateral,
• segmental,
• somatic and
• sympathetic nerve blockade,
which is effective for anaesthesia and analgesia of
unilateral origin from chest and abdomen.

33. Anatomy
TPVS is a wedge shaped space
located on either side of
vertebral column. Boundaries:
• Anterolateral – Parietal
pleura
• Medially – Vertebral body,
intervertebral disc,
intervertebral foramen with
its contents.
• Posterior – Transverse
process and superior
costotransverse ligament.

34. Anatomy
- TPVS contains adipose tissue within which lie
intercostal (spinal) nerves, intercostal vessels,
dorsal & ventral rami and the sympathetic
chain.
- It communicates with epidural space medially
and with intercostal space laterally. It also
communicates with contralateral TPVS
through epidural and prevertebral space.

35. Dermatomal distribution
The dermatomal distribution following a single large volume of LA
varies & unpredictable. So, multiple injection technique where small
volume (3 – 5 ml) of LA injected at several contiguous levels is
preferable.

36. Technique
TPVB can perform in sitting
(preferable), lateral or prone
position.
Skin marking of spinous processes
done for desired number and
level of injection. Skin marking are
also made 2.5 cm lateral to
midline. These markings indicate
needle insertion sites.
A 8cm, 22 G Tuohy needle is
recommended for TPVB.
Two techniques :
• Loss of resistance technique
• Predetermined distance
technique.

37. Note – Due to acute angulation of thoracic spines, the
transverse process that is contacted is the one from
the lower vertebra.

38. Indications

39. Contraindications
• Patient refusal
• Infection at site of injection
• Allergy to LA
• Empyema
• Neoplastic mass occupying TPVS
• Coagulopathy or on anticoagulation therapy
• Caution should be taken in kyphoscoliosis or
deformed spines – as there are increased chances
of inadvertent intrathecal or epidural or pleural
puncture.

40. Complications
• Inadvertent intrathecal, subdural or epidural
injection
• Intravascular injection (LAST)
• Hematoma
• Pleural puncture & Pneumothorax
• Hypotension – less chance because sympathetic
blockade is unilateral.
• Transient ipsilateral Horner’s syndrome – due to
cephalad spread of LA to stellate ganglion.

41. Lumbar paravertebral space (LPVS)
LPVS is a triangular space located on either side of
vertebral column. Boundaries :
• Anterolateral – Psoas major muscle
• Medially - Vertebral body, intervertebral disc,
intervertebral foramen with its contents.
• Posterior – Transverse process and ligaments that
are interposed between adjoining transverse
processes.
- Unlike TPVS, which contains adipose tissue, the
LPVS is occupied primarily by psoas major
muscle.

42. Dermatomal distribution

43. Technique
LPVB can be performed in
sitting (preffered), lateral or
prone position.
Skin marking of spinous
processes done for desired
number and level of injection.
Skin marking are also made 2.5
cm lateral to midline. These
markings indicate needle
insertion sites.
A 8cm, 22 G Tuohy needle is
recommended for TPVB.
Fixed predetermined distance
(1.5 – 2 cm) beyond transverse
process is the most common
method used for LPVB.

44. Indications & Contraindications
• Indications :
i). LPVB is commonly used with TPVB (T10 – L2)
for anaesthesia during inguinal herniorrhaphy.
ii). Analgesia for total hip replacement or any
other hip surgery, pelvic procedures.
• Contraindications : are similar to TPVB.

45. Complications
• Inadvertent intrathecal, or epidural injection
• Intravascular injection (LAST)
• Hematoma
• Nerve injury
• Intraperitoneal or retroperitoneal injection
• Visceral injury (renal).

46. Thank You